High-sensitivity troponin assay does not improve outcomes for MI patients

Dr. Joseph Delano Fule Robles

04 Sep 2018

Prof Nicholas Mills photo from pace-cme.org

The use of high-sensitivity cardiac troponin assays was not associated with a lower subsequent incidence of myocardial infarction (MI) or cardiovascular death at 1 year, according to results of the High-STEACS trial reported at the European Society of Cardiology (ESC) Congress 2018.

In the study among 48,282 patients (mean age, 61 years; 47 percent women) performed between June 2013 and March 2016, the high-sensitivity cardiac troponin I assay reclassified 17 percent of patients with MI or myocardial injury who were not identified by the contemporary assay. [N Engl J Med 2018, doi: 10.1016/ S0140-6736(18)31996-2]

Among those reclassified, subsequent MI or cardiovascular death within 1 year occurred in 15 percent of patients in the validation phase vs 12 percent in the implementation phase (odds ratio [OR], 1.10; 95 percent confidence interval [CI], 0.75 to 1.61; p=0.620).

The validation phase was done for 6–12 months with contemporary cardiac troponin I assay used as a guide for care. The subsequent implementation phase [early (n=5 hospitals) or late (n=5 hospitals)] involved testing patients with the high-sensitivity cardiac troponin I assay immediately or 6 months after the validation phase.

In the reclassified patients, there were also no differences in any secondary efficacy and safety outcome measures between the validation and implementation phases, including all-cause death (OR, 0.71; 95 percent CI, 0.46 to 1.10), hospitalization for heart failure (OR, 1.34; 95 percent CI, 0.84 to 2.16) and ischaemic stroke (OR, 0.85; 95 percent CI, 0.33 to 2.18).

“The trial found that implementation of a high-sensitivity cardiac troponin I assay using the 99th centile as the diagnostic threshold increased the frequency of diagnosing MI. However, use of this method to help diagnose and treat patients was not associated with lower rates of recurrent MI or cardiovascular death in 1 year,” said investigator Professor Nicholas Mills from the University of Edinburgh, UK.

“Among those reclassified, around one-third was diagnosed with type I MI, where treatment guidelines are still lacking. Also, a majority of the reclassified patients were females, where the effectiveness of treatment modalities has not been tested widely,” Mills further commented.

“In the study, sampling and treatment protocols were not according to ESC guidelines, and patients with renal failure, myocarditis and type 2 MI were included. These probably resulted in ‘dilution’ of outcome results,” said discussant Professor Christian Hamm from the University of Glessen, Germany.

The High-STEACS trial is the first randomized trial to evaluate whether the introduction of a high-sensitivity cardiac troponin I assay with a 99th centile diagnostic threshold would reduce subsequent MI or cardiovascular death at 1 year among patients suspected to have acute coronary syndrome.

According to the universal definition of MI, any increase in cardiac troponin above the 99th centile of a healthy reference population should be used as one of the diagnostic criteria for MI. [Eur Heart J
2018, doi: 10.1093/eurheartj/ehy462]